Comparisons
MP3 or MP4: Which Should You Download?
MP4 is the safe default, because the choice only runs one way. Here is when audio-only is the better call, and why some platforms can serve one format and not the other.
Download MP4 unless you are certain you will never need the picture. MP3 is much smaller and plays on anything, but the choice runs one way only: you can pull the audio out of a video afterwards, and you can never put the video back into an audio file.
The choice only runs one way
An MP4 is a container holding a video track and an audio track together. An MP3 holds audio and nothing else. That asymmetry settles most of these arguments before they start. From the MP4 you can extract the sound later, on any device, without going back to the source. From the MP3 there is no route back, because the picture was never in the file.
So MP4 is the safe default, and MP3 is the deliberate choice you make once you have decided the image is worthless to you. A conference talk where the slides carry half the content is not that case. A podcast recorded in a studio is.
Choosing MP3 is a different download, not a smaller one
The natural assumption is that the audio option hands you the same file with the video stripped out. It does not. Audio and video are fetched as separate streams, so asking for MP3 sends a different request, and the result is encoded before anything reaches your device.
Two things follow. One is the pause: a long video sits for a moment before the download begins, and that gap is the conversion running rather than a stalled connection. The other is less obvious. Because it is a separate request, a platform can serve one format perfectly and fail at the other.
Which platforms can give you audio
| Paste this | Video | Audio |
|---|---|---|
| A YouTube video or Short | Yes, up to 1080p | Yes, MP3 at 128 kbps |
| A SoundCloud track | No — the platform is audio-only | Yes |
| A TikTok video | Yes, at the original vertical size | No — the audio request returns an empty file |
That pattern has nothing to do with the tool and everything to do with what each host will hand over. TikTok’s audio endpoint answers with zero bytes, so the TikTok page hides the format toggle instead of handing you an empty file. SoundCloud has no video to serve in the first place. YouTube does both properly, which is why YouTube to MP3 stands as its own page.
When MP3 is genuinely the right call
Speech is the honest case. Lectures, interviews, DJ sets, anything you listen to while walking or driving. An hour of audio at 128 kbps is roughly 58 MB, which is a rounding error next to what an hour of video costs you.
Music is where it turns against you. You are re-compressing something the platform already compressed, and for a track you intend to keep, buying it gets you a better file for a small amount of money. The legal exposure is also real rather than theoretical there. Save what you have the right to save: your own uploads, content a platform offers for download, public posts kept for personal offline use. The platform’s terms still apply to you, whatever any tool happens to let you click.
Where the file lands
Neither format decides that, and it is the part most people skip. A browser download drops into a shared folder that other apps, your backups, and anyone holding your phone can read. On iPhone, Arca takes the same pasted link and encrypts the result on arrival: AES-256-GCM with an Argon2id-derived key, no server, no account. It never passes through your photo library at all. It cannot protect what you have already saved elsewhere, and it makes no claim about the platform you took the file from.
Frequently asked questions
Can I get the audio out of a video I already saved? +
Yes. Any editor or converter on your phone or computer can pull the audio track out of an MP4 without going back to the source. That is why MP4 is the safer default when you are unsure.
Is the MP3 lower quality than the sound in the MP4? +
Slightly, yes. The MP3 is encoded at 128 kbps from audio the platform had already compressed, so it is a second pass of lossy compression. For speech the difference is inaudible. For music you plan to keep, buying the track gets you something meaningfully better.
Why does an MP3 take longer to start downloading? +
The conversion runs on the server before anything is sent, so a long video pauses while the audio is extracted and encoded. That gap is the conversion working, not a stalled connection.
Keep reading
Comparisons
Why the GIF You Saved Is a Video File
You asked for a GIF and got an MP4. That swap did not happen during the download. Platforms convert uploaded GIFs to silent looping video, so the GIF was gone long before you pasted the link anywhere.
Guides
Why Your Downloaded Video Looks Worse Than You Expected
The platform compressed it on upload, long before you downloaded anything. What you can retrieve is the platform's copy, not the creator's original — and no tool can undo that.
Comparisons
Screen Recording vs Downloading a Video: Which Is Better?
Screen recording re-films your display, so it inherits your screen resolution and everything else on it. Downloading keeps the file as published. Here is when each one is the right tool, and the part nobody mentions about where the result lands.
Your photos. Truly private.
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Free to download · iPhone · iOS 18+